langflow-ai/langflow · error · HTTPException

Flow not found

Error message

Flow not found

What it means

Error "Flow not found" thrown in langflow-ai/langflow.

Source

Thrown at src/backend/base/langflow/api/v1/endpoints.py:684

    Raises:
        HTTPException: For flow not found (404) or invalid input (400)
        APIException: For internal execution errors (500)
    """
    # Authorization happens upstream: every caller of _run_flow_internal must
    # have called ensure_flow_permission(FlowAction.EXECUTE, ...) before
    # invoking us. The owner-only check that used to live here would reject any
    # plugin execute-grant on a shared flow, defeating the plugin's
    # purpose. Adding a defense-in-depth check here would re-introduce the
    # same regression.
    telemetry_service = get_telemetry_service()

    # If input_request is None, manually parse the request body
    # This happens when FastAPI can't automatically parse it due to the Request parameter
    if input_request is None:
        input_request = await parse_input_request_from_body(http_request)

    if flow is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Flow not found")

    # Extract request-level variables from headers with prefix X-LANGFLOW-GLOBAL-VAR-*
    request_variables = extract_global_variables_from_headers(http_request.headers)

    # Merge request variables with existing context
    if request_variables:
        if context is None:
            context = {"request_variables": request_variables}
        else:
            context = context.copy()  # Don't modify the original context
            context["request_variables"] = request_variables

    start_time = time.perf_counter()

    if stream:
        asyncio_queue: asyncio.Queue = asyncio.Queue()
        asyncio_queue_client_consumed: asyncio.Queue = asyncio.Queue()
        event_manager = create_stream_tokens_event_manager(queue=asyncio_queue)

View on GitHub (pinned to 976ec789d2)

Solutions

1. Verify the flow id or endpoint name is correct and the flow still exists.
2. Check that the flow belongs to the authenticated user or is shared with them.

When it happens

Trigger: Occurs when the flow referenced by the request (by id or endpoint name) does not exist in the database or is not visible to the current user.

Common situations: See trigger scenarios.

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/19dbbbf194ea46f7. Report an issue: GitHub.